Party Poker 10/20 Hold'em (6 max, 5 handed)

Preflop: Hero is BB with , .
UTG calls, 1 fold, Button raises, SB calls, Hero calls, UTG calls.

Flop: (8 SB) , , (4 players)
SB checks, Hero bets, UTG calls, Button calls, SB calls.

Turn: (6 BB) (4 players)
SB checks, Hero bets, UTG calls, Button folds, SB calls.

River: (9 BB) (3 players)
SB bets, Hero.......

I would most definitely fold.

agree with EP9s analysis. when check caller in ep becomes bettor on the end - it usually means they have a strong hand now [and possibly sooner] and are afraid to check b/c u might check behind them. and the fact there is someone else in the hand means he really isnt afraid of a river raise.

i have seen TPTK played this way, and even that has you beat. if its headsup i prob shake my head and call.